U.S. patent number 9,913,383 [Application Number 15/594,778] was granted by the patent office on 2018-03-06 for printed circuit board and method of fabricating the same.
This patent grant is currently assigned to LG INNOTEK CO., LTD.. The grantee listed for this patent is LG INNOTEK CO., LTD.. Invention is credited to Yun Mi Bae, Dae Young Choi, Jung Ho Hwang, Dong Hun Jeong, In Ho Jeong, Sang Hwa Kim, Soon Gyu Kwon, Han Su Lee, Jin Hak Lee, Sang Young Lee.
United States Patent |
9,913,383 |
Bae , et al. |
March 6, 2018 |
Printed circuit board and method of fabricating the same
Abstract
A printed circuit board includes: an insulating layer; a plating
seed layer disposed on the insulating layer; a circuit pattern
layer disposed on the plating seed layer and formed of copper (Cu);
and a surface treatment layer disposed on the circuit pattern layer
and formed of gold (Au), wherein a width of a bottom surface of the
surface treatment layer is narrower than a width of a top surface
of the plating seed layer, wherein the bottom surface of the
surface treatment layer includes: a first portion contacted with
the circuit pattern layer; and a second portion non contacted with
the circuit pattern layer, and wherein a width of a top surface of
the circuit pattern layer is narrower than a width of a bottom
surface of the circuit pattern layer.
Inventors: |
Bae; Yun Mi (Seoul,
KR), Kwon; Soon Gyu (Seoul, KR), Kim; Sang
Hwa (Seoul, KR), Lee; Sang Young (Seoul,
KR), Lee; Jin Hak (Seoul, KR), Lee; Han
Su (Seoul, KR), Jeong; Dong Hun (Seoul,
KR), Jeong; In Ho (Seoul, KR), Choi; Dae
Young (Seoul, KR), Hwang; Jung Ho (Seoul,
KR) |
Applicant: |
Name |
City |
State |
Country |
Type |
LG INNOTEK CO., LTD. |
Seoul |
N/A |
KR |
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Assignee: |
LG INNOTEK CO., LTD. (Seoul,
KR)
|
Family
ID: |
53887017 |
Appl.
No.: |
15/594,778 |
Filed: |
May 15, 2017 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20170251556 A1 |
Aug 31, 2017 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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14831674 |
Aug 20, 2015 |
9686860 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H05K
3/108 (20130101); H05K 1/11 (20130101); C25D
7/123 (20130101); H05K 1/09 (20130101); H05K
3/244 (20130101); C25D 5/48 (20130101); C25D
3/48 (20130101); H05K 3/188 (20130101); C25D
5/022 (20130101); H05K 3/181 (20130101); H05K
1/0296 (20130101); H05K 2203/1184 (20130101); H05K
2201/099 (20130101); H05K 2201/098 (20130101); C25D
3/38 (20130101); H05K 2201/0338 (20130101); H05K
2201/0989 (20130101) |
Current International
Class: |
H05K
1/09 (20060101); H05K 3/18 (20060101); H05K
3/24 (20060101); C25D 3/48 (20060101); C25D
3/38 (20060101); C25D 5/02 (20060101); C25D
7/12 (20060101); C25D 5/48 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2011-096721 |
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May 2011 |
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JP |
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2012-019080 |
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Jan 2012 |
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JP |
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2012-169597 |
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Sep 2012 |
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JP |
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2010/140725 |
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Dec 2010 |
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WO |
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Other References
European Search Report dated Dec. 20, 2016 for European Application
No. 15181783. cited by applicant .
U.S. Office Action dated Oct. 14, 2016 for U.S. Appl. No.
15/241,714. cited by applicant .
KIPO Office Action dated Sep. 1, 2016 for Korean Patent Application
No. 10-2016-0049000. cited by applicant.
|
Primary Examiner: Norris; Jeremy C
Attorney, Agent or Firm: LRK Patent Law Firm
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. patent application Ser.
No. 14/831,674, filed Aug. 20, 2015, which claimed priority to
Korean Patent Application No. 10-2015-0100404, filed Jul. 15, 2015,
the disclosures of which are incorporated in their entireties
herein by reference.
Claims
What is claimed is:
1. A printed circuit board comprising: an insulating layer; a
plating seed layer disposed on the insulating layer; a circuit
pattern layer disposed on the plating seed layer and formed of
copper (Cu); and a surface treatment layer disposed on the circuit
pattern layer and formed of gold (Au), wherein a width of a bottom
surface of the surface treatment layer is narrower than a width of
a top surface of the plating seed layer, wherein the bottom surface
of the surface treatment layer comprises: a first portion contacted
with the circuit pattern layer; and a second portion non contacted
with the circuit pattern layer, and wherein a width of a top
surface of the circuit pattern layer is narrower than a width of a
bottom surface of the circuit pattern layer.
2. The printed circuit board of claim 1, wherein the circuit
pattern layer includes a corner portion of an upper portion which
has a curvature, and wherein the corner portion of the circuit
pattern layer is a boundary surface between the top surface and a
side surface of the circuit pattern layer, and the boundary surface
has a concavely curved surface.
3. The printed circuit board of claim 1, wherein an uppermost end
of a side surface of the circuit pattern layer is positioned at a
lower level than the top surface of the circuit pattern layer and
the bottom surface of the surface treatment layer.
4. The printed circuit board of claim 1, wherein the circuit
pattern layer includes the top surface which has an inflection
point.
5. The printed board of claim 1, wherein an outermost portion of
the circuit pattern layer is positioned at a lower level than an
inner portion of the first circuit pattern layer.
6. The printed board of claim 1, wherein a thickness of an inner
portion of the circuit pattern layer is greater than that of an
outermost portion of the circuit pattern layer.
7. The printed board of claim 1, wherein a distance between an
outer portion of the top surface of the circuit pattern layer and a
top surface of the insulating layer, measured in a first direction
perpendicular to the top surface of the insulating layer, is
shorter than a distance between an inner portion of the top surface
of the circuit pattern layer and the top surface of the insulating
layer, measured in the first direction.
8. The printed board of claim 1, wherein the bottom surface of the
circuit pattern layer comprises a first area vertically overlapped
with the top surface of the circuit pattern layer and a second area
except for the first area, wherein the second area comprises a
third area that is not vertically overlapped with the second
portion of the surface treatment layer and a fourth area vertically
overlapped with the second portion of the surface treatment layer,
and wherein the third area has a width wider than a width of the
fourth area.
9. The printed circuit board of claim 1, wherein the bottom surface
of the surface treatment layer has a width narrower than a width of
a bottom surface of the circuit pattern layer.
10. The printed circuit board of claim 1, wherein the second
portion of the surface treatment layer is floated on the circuit
pattern layer.
11. The printed circuit board of claim 1, wherein the plating seed
layer serves as a seed layer for the circuit pattern layer and the
surface treatment layer.
12. The printed circuit board of claim 1, wherein at least one of a
left lateral side and a right lateral side of the circuit pattern
layer comprises a first portion substantially perpendicular to a
bottom surface of the circuit pattern layer and a second portion
extending from the first part and having a curved surface.
13. A printed circuit board comprising: an insulating layer; a
circuit pattern layer disposed on the insulating layer and formed
of copper (Cu); and a surface treatment layer disposed on the
circuit pattern layer and formed of gold (Au), wherein the bottom
surface of the surface treatment layer comprises: a first portion
contacted with the circuit pattern layer; and a second portion non
contacted with the circuit pattern layer, wherein a width of a top
surface of the circuit pattern layer is narrower than a width of a
bottom surface of the circuit pattern layer, and wherein the
circuit pattern layer is in direct contact with the surface
treatment layer without having a nickel metal layer
therebetween.
14. The printed board of claim 13, further comprising a plating
seed layer disposed between the insulating layer and the circuit
pattern layer, wherein a width of a bottom surface of the surface
treatment layer is narrower than a width of a top surface of the
plating seed layer.
15. The printed circuit board of claim 13, wherein the circuit
pattern layer includes a corner portion of an upper portion which
has a curvature, and wherein the corner portion of the circuit
pattern layer is a boundary surface between a top surface and a
side surface of the circuit pattern layer, and the boundary surface
has a concavely curved surface.
16. The printed circuit board of claim 13, wherein an uppermost end
of a side surface of the circuit pattern layer is positioned at a
lower level than the top surface of the circuit pattern layer and
the bottom surface of the surface treatment layer.
17. The printed circuit board of claim 13, wherein the second
portion of the surface treatment layer is floated on the circuit
pattern layer.
18. The printed board of claim 13, wherein a distance between an
outer portion of the top surface of the circuit pattern layer and a
top surface of the insulating layer, measured in a first direction
perpendicular to the top surface of the insulating layer, is
shorter than a distance between an inner portion of the top surface
of the circuit pattern layer and the top surface of the insulating
layer, measured in the first direction.
19. The printed board of claim 13, wherein the bottom surface of
the circuit pattern layer comprises a first area vertically
overlapped with the top surface of the circuit pattern layer and a
second area except for the first area, wherein the second area of
the circuit pattern layer comprises a third area that is not
vertically overlapped with the second portion of the surface
treatment layer and a fourth area vertically overlapped with the
second portion of the surface treatment layer, and wherein the
third area has a width wider than a width of the fourth area.
20. The printed circuit board of claim 13, wherein at least one of
a left lateral side and a right lateral side of the circuit pattern
layer comprises a first portion substantially perpendicular to a
bottom surface of the circuit pattern layer and a second portion
extending from the first portion and having a curved surface.
Description
BACKGROUND
The disclosure relates to a printed circuit board, and more
particularly to a printed circuit board, which includes a circuit
pattern having a curved surface in a portion of a lateral side
thereof and a surface treatment layer formed through electrolytic
plating, and a method of fabricating the same.
A printed circuit board (PCB), which is formed by printing a
circuit line pattern on an electrically insulating substrate using
a conductive material, such as copper (Cu), signifies a board
immediately before electronic components are mounted thereon. That
is to say, the PCB signifies a circuit board in which the mounting
positions of the electronic components are determined, and circuit
patterns are printed on and fixed to the surface of a flat plate to
connect the electronic components with each other, in order to
densely mount various types of electronic devices on the flat
plate.
In general, for the surface treatment of the circuit patterns
formed on the PCB, Organic Solderability Preservative (OSP) has
been used, and electrolytic nickel/gold, electrolytic
nickel/gold-cobalt alloy, or electroless nickel/palladium/gold has
been used.
In this case, various surface treatment schemes may be employed
according to the use purposes thereof. For example, the surface
treatment schemes for soldering, wire-bonding, and a connector may
be used.
FIG. 1 is a sectional view showing a PCB according to the related
art.
Referring to (a) and (b) of FIG. 1, the PCB includes an insulating
layer 10, a plating seed layer 20, a circuit pattern 30, a
protective layer 40, a first surface treatment layer 50, and a
second surface treatment layer 60.
In FIGS. 1, (a) and 1(b) show the insulating layer 10, the plating
seed layer 20, the circuit pattern 30, the first surface treatment
layer 50, and the second surface treatment layer 60 having the same
structures except for protective layers 40 having different
structures according to the used shape thereof.
In other words, the protective layer 40 shown in (a) of FIG. 1
covers the entire exposed surface of the insulating layer 10 while
covering at least a portion of a top surface of the circuit pattern
30, and has a shape of protruding upward from the surface of the
second surface treatment layer 60.
The protective layer 40 shown in (b) of FIG. 1 serves only as an
embankment. Accordingly, the protective layer 40 exposes at least a
portion of the surface of the insulating layer 10 in the state that
the protective layer 40 does not make contact with the circuit
pattern 30.
Meanwhile, the above PCB according to the related art includes the
first surface treatment layer 50 including nickel (Ni) and the
second surface treatment layer 60 including gold (Au) for the
surface treatment of the circuit pattern 30.
In this case, the first surface treatment layer 50 and the second
surface treatment layer 60 are generally formed through electroless
plating since a seed layer for electroplating does not separately
exist.
In addition, to form the first and second surface treatment layers
50 and 60 through the electrolytic plating, a plating seed layer
must be additionally formed.
However, design limitations may exist as the additional seed layer
is formed in order to perform the electroplating even though the
surface treatment of the PCB is generally performed through the
electroless plating.
In addition, the surface treatment of the PCB essentially requires
the formation of the first surface treatment layer 50 including
metal, such as Ni, for the diffusion of the circuit pattern 30
including Cu.
SUMMARY
In one general aspect, there is provided a printed circuit board
comprising: an insulating layer; a plating seed layer disposed on
the insulating layer; a circuit pattern layer disposed on the
plating seed layer and formed of copper (Cu); and a surface
treatment layer disposed on the circuit pattern layer and formed of
gold (Au), wherein a width of a bottom surface of the surface
treatment layer is narrower than a width of a top surface of the
plating seed layer, wherein the bottom surface of the surface
treatment layer comprises: a first portion contacted with the
circuit pattern layer; and a second portion non contacted with the
circuit pattern layer, and wherein a width of a top surface of the
circuit pattern layer is narrower than a width of a bottom surface
of the circuit pattern layer.
The circuit pattern layer may include a corner portion of an upper
portion which has a curvature, the corner portion of the circuit
pattern layer may be a boundary surface between the top surface and
a side surface of the circuit pattern layer, and the boundary
surface may have a concavely curved surface.
An uppermost end of a side surface of the circuit pattern layer may
be positioned at a lower level than the top surface of the circuit
pattern layer and the bottom surface of the surface treatment
layer.
The circuit pattern layer may include the top surface which has an
inflection point.
An outermost portion of the circuit pattern layer may be positioned
at a lower level than an inner portion of the first circuit pattern
layer.
A thickness of an inner portion of the circuit pattern layer may be
greater than that of an outermost portion of the circuit pattern
layer.
A distance between an outer portion of the top surface of the
circuit pattern layer and a top surface of the insulating layer,
measured in a first direction perpendicular to the top surface of
the insulating layer, may be shorter than a distance between an
inner portion of the top surface of the circuit pattern layer and
the top surface of the insulating layer, measured in the first
direction.
The bottom surface of the circuit pattern layer may comprise a
first area vertically overlapped with the top surface of the
circuit pattern layer and a second area except for the first area,
the second area may comprise a third area that is not vertically
overlapped with the second portion of the surface treatment layer
and a fourth area vertically overlapped with the second portion of
the surface treatment layer, and the third area may have a width
wider than a width of the fourth area.
The bottom surface of the surface treatment layer may have a width
narrower than a width of a bottom surface of the circuit pattern
layer.
The second portion of the surface treatment layer may be floated on
the circuit pattern layer.
The plating seed layer may serve as a seed layer for the circuit
pattern layer and the surface treatment layer.
At least one of a left lateral side and a right lateral side of the
circuit pattern layer may comprise a first portion substantially
perpendicular to a bottom surface of the circuit pattern layer and
a second portion extending from the first part and having a curved
surface.
In another general aspect, there is provided a printed circuit
board comprising: an insulating layer; a circuit pattern layer
disposed on the insulating layer and formed of copper (Cu); and a
surface treatment layer disposed on the circuit pattern layer and
formed of gold (Au), wherein the bottom surface of the surface
treatment layer comprises: a first portion contacted with the
circuit pattern layer; and a second portion non contacted with the
circuit pattern layer, wherein a width of a top surface of the
circuit pattern layer is narrower than a width of a bottom surface
of the circuit pattern layer, and wherein the circuit pattern layer
is in direct contact with the surface treatment layer without
having a nickel metal layer therebetween.
The printed board may further comprise a plating seed layer
disposed between the insulating layer and the circuit pattern
layer, wherein a width of a bottom surface of the surface treatment
layer is narrower than a width of a top surface of the plating seed
layer.
The circuit pattern layer may include a corner portion of an upper
portion which has a curvature, the corner portion of the circuit
pattern layer may be a boundary surface between a top surface and a
side surface of the circuit pattern layer, and the boundary surface
may have a concavely curved surface.
An uppermost end of a side surface of the circuit pattern layer may
be positioned at a lower level than the top surface of the circuit
pattern layer and the bottom surface of the surface treatment
layer.
The second portion of the surface treatment layer may be floated on
the circuit pattern layer.
A distance between an outer portion of the top surface of the
circuit pattern layer and a top surface of the insulating layer,
measured in a first direction perpendicular to the top surface of
the insulating layer, may be shorter than a distance between an
inner portion of the top surface of the circuit pattern layer and
the top surface of the insulating layer, measured in the first
direction.
The bottom surface of the circuit pattern layer may comprise a
first area vertically overlapped with the top surface of the
circuit pattern layer and a second area except for the first area,
the second area of the circuit pattern layer may comprise a third
area that is not vertically overlapped with the second portion of
the surface treatment layer and a fourth area vertically overlapped
with the second portion of the surface treatment layer, and the
third area may have a width wider than a width of the fourth
area.
At least one of a left lateral side and a right lateral side of the
circuit pattern layer may comprise a first portion substantially
perpendicular to a bottom surface of the circuit pattern layer and
a second portion extending from the first portion and having a
curved surface.
Technical objects of the embodiments may not be limited to the
above object and other technical objects of the embodiments will be
apparent to those skilled in the art from the following
description. The details of one or more embodiments are set forth
in the accompanying drawings and the description below. Other
features will be apparent from the description and drawings, and
from the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view showing a printed circuit board
according to the related art.
FIG. 2 is a sectional view showing the structure of a printed
circuit board according to the first embodiment of the
disclosure.
FIG. 3 is a sectional view showing the circuit pattern of FIG. 2 in
detail.
FIGS. 4 to 11 are sectional views showing a method of fabricating
the printed circuit board of FIG. 2 in process sequence.
FIG. 12 is a sectional view showing the structure of a printed
circuit board according to the second embodiment of the
disclosure.
FIGS. 13 to 15 are sectional views showing a method of fabricating
the printed circuit board of FIG. 12.
FIG. 16 is a sectional view showing the structure of a printed
circuit board according to the third embodiment of the
disclosure.
FIG. 17 is a sectional view showing the structure of a printed
circuit board according to the fourth embodiment of the
disclosure.
FIG. 18 is a sectional view showing the structure of a printed
circuit board according to the fifth embodiment of the
disclosure.
DETAILED DESCRIPTION OF THE EMBODIMENTS
Hereinafter, embodiments of the disclosure will be described in
detail with reference to accompanying drawings so that those
skilled in the art can easily replicate with the embodiments.
However, the embodiments may have various modifications, and the
disclosure is not limited thereto.
In the following description, when a predetermined part "includes"
a predetermined element, the predetermined part does not exclude
other elements, but may further include other components unless
otherwise indicated.
The thickness and size of each layer shown in the drawings may be
exaggerated, omitted or schematically drawn for the purpose of
convenience or clarity. In addition, the size of elements does not
utterly reflect an actual size. The same reference numbers will be
assigned the same elements throughout the drawings.
In the description of the embodiments, it will be understood that,
when a layer, a film, a region, or a plate is referred to as being
"on" another layer, another film, another region, or another plate,
it can be "directly" on the other layer, film, region, plate, or
one or more intervening layers may also be present. Meanwhile, it
will be understood that, when a layer, a film, a region, or a plate
is referred to as being "directly on" another layer, another film,
another region, or another plate, any intervening layer is not
present.
The disclosure provides a printed circuit board, in which a
conventional Ni surface treatment layer may be omitted by forming a
surface treatment layer using a removable film-type material and an
additional seed layer, and a portion of the top surface of the
circuit pattern may be removed together with the seed layer when
the seed layer is removed.
FIG. 2 is a sectional view showing the structure of a printed
circuit board according to the first embodiment of the disclosure.
FIG. 3 is a sectional view showing the circuit pattern of FIG. 2 in
detail.
Referring to FIGS. 2 and 3, a printed circuit board 100 includes an
insulating layer 110, a plating seed layer 120, a circuit pattern
130, and a surface treatment layer 140.
The insulating layer 110 may mean a support substrate of the
printed circuit board 100 having a single circuit pattern, and mean
an insulating layer area having one circuit pattern 130 in a
printed circuit board having a plurality of lamination
structures.
When the insulating layer 110 means one insulating layer
constituting the plural lamination structures, a plurality of
circuit patterns may be continuously formed on top and bottom
surfaces of the insulating layer 110.
The insulating layer 110 may constitute an insulating plate, and
may include a thermosetting or thermoplastic polymeric substrate, a
ceramic substrate, an organic-inorganic composite substrate, or a
glass fiber impregnated substrate. If the insulating layer 110
includes the polymeric resin, the insulating layer may include
epoxy insulating resin, or may include polyimide based resin.
The insulating layer 110 is formed thereon with the circuit pattern
130.
Preferably, the plating seed layer 120 to be used when the circuit
pattern 130 is formed is formed between the insulating layer 110
and the circuit pattern 130.
The top and bottom surfaces of the plating seed layer 120 may have
equal widths.
Then, the circuit pattern 130 is formed on the plating seed layer
120.
Differently from the plating seed layer 120, the circuit pattern
130 may be formed in a shape in which the top and bottom surfaces
thereof have mutually different widths. In this case, the width of
the bottom surface of the circuit pattern 130 may be equal to the
width of the top surface or the bottom surface of the plating seed
layer 120, and the width of the top surface of the circuit pattern
130 may be narrower than that of the bottom surface of the circuit
pattern 130.
The plating seed layer 120 and the circuit pattern 130 may be
formed of metal including copper (Cu) and having electrical
conductivity.
The circuit pattern 130 may be formed through an additive process,
a subtractive process, a modified semi-additive process (MSAP), or
a semi-additive process (SAP), which is a typical process of
fabricating a printed circuit board, and the details thereof will
be omitted.
Although drawings show that a single circuit pattern 130 is formed
on the insulating layer 110, a plurality of circuit patterns 130
may be formed on at least one of the top and bottom surfaces of the
insulating layer 110 while being spaced apart from each other.
Hereinafter, the circuit pattern 130 will be described in more
detail with reference to FIG. 3. The circuit pattern 130 includes a
first part 131 formed on the plating seed layer 120 to have a
bottom surface making contact with the top surface of the plating
seed layer 120, and a second part 132 formed on the first part 131
to have at least a portion of a top surface making contact with the
bottom surface of the surface treatment layer 140.
Although the circuit pattern 130 includes the first part 131 and
the second part 132, the first and second parts 131 and 132 are
provided only for the purpose of explaining the shape of the
circuit pattern 130. Actually, the first and second parts 131 and
132 may be integrated with each other as one component.
The bottom surface of the first part 131 of the circuit pattern 130
directly makes contact with the top surface of the plating seed
layer 120.
In this case, the first part 131 of the circuit pattern 130 may
have a shape in which the top and bottom surfaces of the first part
131 have equal widths.
In addition, the second part 132 of the circuit pattern 130 has
mutually different widths at the bottom and top surfaces
thereof.
In other words, in the second part 132 of the circuit pattern 130,
the width of the top surface is narrower than that of the bottom
surface. Accordingly, the lateral side of the second part 132 is
formed with a predetermined curvature lengthwise.
In this case, the second part 132 of the circuit pattern 130 may
include a first lateral side having a first curvature and a second
lateral side having a second curvature. In addition, the first
curvature of the first lateral side may be substantially equal to
the second curvature of the second lateral side.
Therefore, the circuit pattern 130 has left and right lateral
sides. Each of the left and right lateral sides includes a first
portion substantially perpendicular to a main surface and a second
portion extending from the first portion and including a curved
surface having a predetermined curvature.
The surface treatment layer 140 is formed on the circuit pattern
130 for the surface treatment of the circuit pattern 130.
The surface treatment layer 140 may be formed of metal including
gold (Au) or the alloy including Au.
When the surface treatment layer 140 is formed of the alloy
including Au, the surface treatment layer 140 may be formed of the
Au alloy including cobalt (Co). In this case, the surface treatment
layer 140 is formed through the electrolytic plating.
Preferably, the surface treatment layer 140 is formed by performing
the electroplating with respect to the plating seed layer 120 that
is the same as the plating seed layer used when the circuit pattern
130 is formed.
The surface treatment layer 140 is formed on the circuit pattern
130. Accordingly, the bottom surface of the surface treatment layer
140 directly makes contact with the top surface of the circuit
pattern 130.
In this case, the surface treatment layer 140 includes the bottom
surface having the width wider than that of the top surface of the
circuit pattern 130.
Accordingly, the bottom surface of the surface treatment layer 140
includes a first bottom surface directly making contact with the
top surface of the circuit pattern 130 and a second bottom surface
that does not make contact with the top surface of the circuit
pattern 130.
In this case, the first bottom surface of the surface treatment
layer 140 may be the central area of the bottom surface of the
surface treatment layer 140, and second bottom surfaces of the
surface treatment layer 140 may be left and right areas of the
surface treatment layer 140.
In addition, the surface treatment layer 140 may have a shape in
which the width of the top surface is equal to that of the bottom
surface.
Meanwhile, the top and bottom surfaces of the surface treatment
layer 140 may have widths narrower than that of the bottom surface
of the circuit pattern 130.
Accordingly, as shown in FIG. 2, the surface treatment layer 140
has an cave structure of protruding outward from the upper lateral
side of the circuit pattern 130.
As described above, according to the disclosure, the surface
treatment layer 140 including Au is formed using the plating seed
layer 120 used when the circuit pattern 130 is formed, the nickel
(Ni) surface treatment layer serving as the seed layer of the gold
(Au) surface treatment layer may be removed.
In addition, as described above, according to the disclosure, the
conventional nickel (Ni) surface treatment layer is omitted, and
the surface treatment layer 140 including gold (Au) is formed
directly on the circuit pattern 130, thereby increasing the
electrical conductivity, and reducing the electrical resistance.
Accordingly, the RF characteristic may be improved.
In addition, as described above, according to the disclosure, the
surface treatment layer 140 formed on the circuit pattern 130 has
an eave structure of protruding outward from the upper lateral side
of the circuit pattern 130, so that the mounting area of the
components mounted on the circuit pattern may be increased.
Accordingly, the reliability of a customer may be improved.
Hereinafter, the relationship between the circuit pattern 130 and
the surface treatment layer 140 will be described in more
detail.
Referring to FIG. 2, the circuit pattern 130 has the top surface
and the bottom surface having widths different from each other. In
this case, the bottom surface of the circuit pattern 130 has a
first width W1, and the top surface of the circuit pattern 130 has
the second width W2 narrower than the first width W1.
Accordingly, the bottom surface of the circuit pattern 130 includes
a second area vertically overlapped with the top surface of the
circuit pattern 130, and a first area that is not overlapped with
the top surface of the circuit pattern 130.
In addition, the surface treatment layer 140 is formed on the
circuit pattern 130, and the top surface and the bottom surface of
the surface treatment layer 140 have equal third widths W3.
In this case, the third width W3 is narrower than the first width
W1 and wider than the second width W2.
Accordingly, the bottom surface of the surface treatment layer 140
includes a contact area making contact with the top surface of the
circuit pattern 130 and a non-contact area that protrudes outward
of the top surface of the circuit pattern 130 beyond the contact
area and does not make contact with the top surface of the circuit
pattern 130.
In this case, the bottom surface of the circuit pattern 130 may
have a width wider than that of the top surface of the circuit
pattern 130 by a fourth width W4.
That is to say, the first area of the circuit pattern 130 may have
the fourth width W4.
In this case, the first area of the circuit pattern 130 is
partially overlapped with the non-contact area of the surface
treatment layer 140.
In other words, the first area of the circuit pattern 130 includes
a third area that is not vertically overlapped with the non-contact
area of the surface treatment layer 140 and has a fifth width W5,
and a fourth area that is vertically overlapped with the
non-contact area of the surface treatment layer 140 and has a sixth
width W6.
In this case, preferably, the fifth width W5 of the third area is
wider than the sixth width W6 of the fourth area.
More preferably, the ratio of the fifth width W5 to the sixth width
W6 is in the range of 1.5 to 4.0.
In other words, when the ratio of the fifth width W5 to the sixth
width W6 is less than 1.5, the non-contact area of the surface
treatment layer 140 has a wider area. In this case, the non-contact
area of the surface treatment layer 140 protruding outward of the
top surface of the circuit pattern 130 has an unstable structure,
so that the non-contact area may be collapsed, thereby causing the
electrical short.
In addition, when the ratio of the fifth width W5 to the sixth
width W6 is more than 4.0, the non-contact area of the surface
treatment layer 140 has a narrower width. In this case, as the
entire width of the surface treatment layer 140 is narrowed, the
mounting area may be narrowed.
Therefore, according to the disclosure, when the surface treatment
layer 140 having the eave structure is formed as described above,
the ratio of the fifth width W5 to the sixth width W6 satisfies the
range of 1.5 to 4.0. In this case, the fifth width W5 is wider than
the sixth width W6, so that the fifth width W5 has a value ranging
from 1.5 to 4 times that of the sixth width W6.
Hereinafter, a method of fabricating the printed circuit board
shown in FIG. 2 will be described in detail with reference to FIGS.
4 to 11.
FIGS. 4 to 11 are sectional views showing the method of fabricating
the printed circuit board of FIG. 2 in process sequence.
Referring to FIG. 4, after preparing the insulating layer 110, the
plating seed layer 120 is formed on the prepared insulating layer
110.
The plating seed layer 120 may be formed by performing electroless
plating with respect to the insulating layer 110 using metal
including Cu.
The insulating layer 110 may include a thermosetting or
thermoplastic polymeric substrate, a ceramic substrate, an
organic-inorganic composite substrate, or a glass fiber impregnated
substrate. If the insulating layer 110 includes the polymeric
resin, the insulating layer 110 may include epoxy insulating resin,
or may include polyimide based resin.
The plating seed layer 120 may be formed by performing typical
copper clad laminate (CCL) instead of the electroless plating with
respect to the surface of the insulating layer 110.
In this case, when the plating seed layer 120 is formed through the
electroless plating, surface roughness is applied to the top
surface of the insulating layer 110, so that the electroless
plating may be smoothly performed.
The electroless plating scheme may be performed in the sequence of
a degreasing process, a soft etching process, a pre-catalyst
process, a catalyst treatment process, an accelerator process, an
electroless plating process, and an anti-oxidation treatment
process. In addition, the plating seed layer 120 may be formed by
sputtering metallic particles using plasma.
In this case, before forming the plating seed layer 120 through the
plating process, a desmear process of removing smears from the
surface of the insulating layer 110 may be additionally performed.
The desmear process is performed to enhance plating power for the
formation of the plating seed layer 120 by applying surface
roughness onto the surface of the insulating layer 11.
Thereafter, referring to FIG. 5, a first mask 125 is formed on the
plating seed layer 120. In this case, the first mask 125 may
include a dry film.
In this case, the first mask 125 has an opening a to expose at
least a portion of the top surface of the plating seed layer
120.
In this case, the top surface of the plating seed layer 120 exposed
by the opening a of the first mask 125 corresponds to an area for
the circuit pattern 130.
In other words, the first mask 125 having the opening a to expose
the area for the circuit pattern 130 in the top surface of the
plating seed layer 120 is formed on the plating seed layer 120.
In this case, the first mask 125 may be formed to cover the whole
top surface of the plating seed layer 120. Accordingly, the opening
a may be formed by removing a portion of an area of the plating
seed layer 120 for the formation of the circuit pattern 130.
Next, referring to FIG. 6, the circuit pattern 130 is formed on the
plating seed layer 120 so that the circuit pattern 130 is filled in
at least a portion of the opening a of the first mask 125.
The circuit pattern 130 may be formed while being filled in the at
least a portion of the opening a of the first mask 125 by
performing electroplating with respect to the plating seed layer
120 serving as a seed layer using a conductive material,
preferably, the alloy including Cu.
Next, referring to FIG. 7, the first mask 125 is removed from the
plating seed layer 120.
In this case, after the first mask 125 has been removed, the
residues of the first mask 125 may remain on the surface of the
plating seed layer 120. Accordingly, an additional process of
removing the residues of the first mask 125 may be performed.
Then, referring to FIG. 8, a second mask 135 is formed on the
plating seed layer 120.
In this case, preferably, the second mask 135 may include a dry
film having strong heat resistance and an easy removable
property.
The second mask 135 includes an opening b to expose the top surface
of the circuit pattern 130.
In this case, the opening b of the second mask 135 is formed with a
width narrower than that of the top surface of the circuit pattern
130.
Accordingly, at least a portion of the top surface of the circuit
pattern 130 is covered by the second mask 135. Preferably, the
central area of the top surface of the circuit pattern 130 is
exposed to the outside by the opening b of the second mask 135, and
the edge areas of the top surface of the circuit pattern 130 is
covered by the second mask 135.
Next, referring to FIG. 9, the surface treatment layer 140 is
formed on the circuit pattern 130 by employing both of the plating
seed layer 120 and the circuit pattern 130 as a seed layer.
In this case, the surface treatment layer 140 is formed with a
width equal to that of the opening b of the second mask 135.
The surface treatment layer 140 may be formed of metal including
only gold (Au) or the alloy including Au.
When the surface treatment layer 140 is formed of the alloy
including Au, the surface treatment layer 140 may be formed of the
Au alloy including Co. In this case, the surface treatment layer
140 may be formed through the electroless plating.
Preferably, the surface treatment layer 140 is formed by performing
the electroplating with respect to the plating seed layer 120 which
is the same as a plating seed layer used when the circuit pattern
130 is formed. In other words, the surface treatment layer 140 is
formed through the electroplating as the plating seed layer 120 is
connected with the circuit pattern 130 so that a short occurs
between the plating seed layer 120 and the circuit pattern 130.
The surface treatment layer 140 is formed on the circuit pattern
130 so that the bottom surface of the surface treatment layer 140
directly makes contact with the top surface of the circuit pattern
130.
In this case, the surface treatment layer 140, which exists before
the plating seed layer 120 is removed, includes top and bottom
surfaces having widths narrower than that of the top surface of the
circuit pattern 130.
Accordingly, the top surface of the circuit pattern 130 includes a
part that makes contact with the surface treatment layer 140 and a
part that does not make contact with the surface treatment layer
140.
Next, referring to FIG. 10, the second mask 135 formed on the
plating seed layer 120 is removed.
In this case, if the second mask 135 is removed similarly to the
process of removing the first mask 125, an additional process may
be performed to remove the residues of the second mask 135
remaining on the plating seed layer 120.
Thereafter, referring to FIG. 11, a process of removing a portion
of the plating seed layer 120, which is formed on the insulating
layer 110 and has no the circuit pattern 130, is performed.
In other words, after the second mask 135 has been removed, the
process of removing the portion of the plating seed layer 120
formed on the insulating layer 110 is performed. In this case, when
the process of removing the plating seed layer 120 is performed, a
portion of the plating seed layer 120 which is formed under the
circuit pattern 130 is not removed due to the circuit pattern 130,
but only the portion of the plating seed layer 120 having no
circuit pattern 130 is selectively removed.
In this case, edge areas of the top surface of the circuit pattern
130 have no the surface treatment layer 140. Accordingly, when the
process of removing the portion of the plating seed layer 120,
which is formed on the insulating layer 110 and has no the circuit
pattern 130, is performed, the edge areas of the top surface of the
circuit pattern 130, which are not covered by the surface treatment
layer 140, are also removed.
In this case, only a portion of the top surface of the circuit
pattern 130, which is not covered by the surface treatment layer
140, is removed.
Accordingly, upper lateral sides of the circuit pattern 130 are
removed with a predetermined curvature differently from the lower
portion of the circuit pattern 130.
Therefore, the bottom surface of the surface treatment layer 140
may have the width wider than that of the top surface of the
circuit pattern 130.
In addition, due to the process of removing the above plating seed
layer 120, the bottom surface of the surface treatment layer 140
includes a first bottom surface directly making contact with the
top surface of the circuit pattern 130 and second bottoms surface
that does not make contact with the top surface of the circuit
pattern 130.
In this case, the first bottom surface of the surface treatment
layer 140 may be the central area of the bottom surface of the
surface treatment layer 140, and the second bottom surfaces of the
surface treatment layer 140 may be left and right areas of the
surface treatment layer 140.
Meanwhile, the top and bottom surfaces of the surface treatment
layer 140 may have the widths narrower than the width of the bottom
surface of the circuit pattern 130.
In other words, as the edge areas of the upper portion of the
circuit pattern 130 are removed in the process of removing the
plating seed layer 120, the circuit pattern 130 may be divided into
the first part 131 and the second part 132 as described above.
The bottom surface of the first part 131 of the circuit pattern 130
directly makes contact with the top surface of the plating seed
layer 120.
In this case, the first part 131 of the circuit pattern 130 has a
shape in which the top surface and the bottom surface of the first
part 131 have equal widths.
In addition, the second part 132 of the circuit pattern 130 has a
shape in which the top surface and the bottom surface have mutually
different widths.
In other words, in the second part 132 of the circuit pattern 130,
the width of the top surface is narrower than that of the bottom
surface. Accordingly, the lateral sides of the second part 132 are
formed with a predetermined curvature lengthwise.
In this case, the second part 132 of the circuit pattern 130 may
include the first lateral side having the first curvature and the
second lateral side having the second curvature. In addition, the
first curvature of the first lateral side may be substantially
equal to the second curvature of the second lateral side.
Therefore, the circuit pattern 130 has left and right lateral
sides, and each of the left and right lateral sides includes a
first portion substantially perpendicular to a main surface and a
second portion extending from the first portion and including a
curved surface having a predetermined curvature.
Accordingly, as shown in FIG. 2, the surface treatment layer 140
has the cave structure of protruding outward from the upper lateral
side of the circuit pattern 130.
As described above, according to the disclosure, the surface
treatment layer 140 including Au is formed by utilizing the plating
seed layer 120 used when the circuit pattern 130 is formed, so that
the nickel (Ni) surface treatment layer serving as the seed layer
for the gold (Au) surface treatment layer may be omitted.
In addition, as described above, according to the disclosure, the
conventional nickel (Ni) surface treatment layer is omitted, and
the surface treatment layer 140 including gold (Au) is formed
directly on the circuit pattern 130, thereby increasing the
electrical conductivity, and reducing the electrical resistance.
Accordingly, the RF characteristic may be improved.
In addition, as described above, according to the disclosure, the
surface treatment layer 140 formed on the circuit pattern 130 has
the cave structure of protruding outward from the upper lateral
side of the circuit pattern 130, so that the mounting area of the
components mounted on the circuit pattern may be increased.
Accordingly, the reliability of a customer may be improved.
FIG. 12 is a sectional view showing the structure of a printed
circuit board according to the second embodiment of the
disclosure.
Referring to FIG. 12, a printed circuit board 200 includes an
insulating layer 210, a plating seed layer 220, a circuit pattern
230, and a surface treatment layer 240.
The insulating layer 210 may mean a support substrate of the
printed circuit board 100 having a single circuit pattern, and mean
an insulating layer area having one circuit pattern 230 in a
printed circuit board having a plurality of lamination
structures.
The insulating layer 210 may constitute an insulating plate, and
may include a thermosetting or thermoplastic polymeric substrate, a
ceramic substrate, an organic-inorganic composite substrate, or a
glass fiber impregnated substrate. If the insulating layer 210
includes the polymeric resin, the insulating layer 210 may include
epoxy insulating resin, or may include polyimide based resin.
The circuit pattern 230 is formed on the insulating layer 210.
Preferably, the plating seed layer 120 for the formation of the
circuit pattern 230 is formed between the insulating layer 210 and
the circuit pattern 230.
The top and bottom surfaces of the plating seed layer 220 may have
equal widths.
In addition, the circuit pattern 230 is formed on the plating seed
layer 220.
Differently from the plating seed layer 220, the circuit pattern
230 may have a shape in which the top and bottom surfaces thereof
have mutually different widths. In this case, the width of the
bottom surface of the circuit pattern 230 may be equal to that of
the top surface or the bottom surface of the plating seed layer
220. The width of the top surface of the circuit pattern 230 may be
narrower than that of the bottom surface of the circuit pattern
230.
The plating seed layer 220 and the circuit pattern 230 are formed
of metal including Cu and having electrical conductivity.
The circuit pattern 230 may be formed through an additive process,
a subtractive process, a modified semi-additive process (MSAP), or
a semi-additive process (SAP), which is a typical process of
fabricating a printed circuit board, and the details thereof will
be omitted.
Although drawings show that a single circuit pattern 230 is formed
on the insulating layer 210, a plurality of circuit patterns 230
may be formed on at least one of the top surface and the bottom
surface of the insulating layer 210 while being spaced apart from
each other by a predetermined distance.
In this case, the circuit pattern 230 may have a shape similar to
that of the circuit pattern 130 according to the first embodiment.
Although both lateral sides of the circuit pattern 130 according to
the first embodiment have a predetermined curvature, the circuit
pattern 230 according to the second embodiment has a predetermined
curvature only at an upper right lateral side thereof.
In other words, the left lateral side of the circuit pattern 230 is
substantially perpendicular to the bottom surface of the circuit
pattern 230, and the right lateral side of the circuit pattern 230
has a portion substantially perpendicular to the bottom surface of
the circuit pattern 230 and a curved surface portion extending from
the perpendicular portion and having a predetermined curvature.
The surface treatment layer 240 is formed on the circuit pattern
230 to perform the surface treatment of the circuit pattern
230.
The surface treatment layer 240 may be formed of metal including
only Au or the alloy including Au.
When the surface treatment layer 240 is formed of the alloy
including Au, the surface treatment layer 240 may be formed of the
Au alloy including Co. In this case, the surface treatment layer
240 is formed through electroless plating.
Preferably, the surface treatment layer 240 is formed by performing
the electroplating with respect to the plating seed layer 220 which
is the same as the plating seed layer used when the circuit pattern
230 is formed.
The surface treatment layer 240 is formed on the circuit pattern
230, so that the bottom surface of the surface treatment layer 240
directly makes contact with the top surface of the circuit pattern
230.
In this case, the surface treatment layer 240 includes the bottom
surface having a width wider than that of the top surface of the
circuit pattern 230.
Accordingly, the bottom surface of the surface treatment layer 240
includes a first bottom surface that directly makes contact with
the top surface of the circuit pattern 230 and a second bottom
surface that does not make contact with the top surface of the
circuit pattern 230.
In this case, the first bottom surface of the surface treatment
layer 240 may include the central area and a left area of the
bottom surface of the surface treatment layer 240, and the second
bottom surface of the surface treatment layer 240 may include a
right area of the surface treatment layer 240.
In addition, the surface treatment layer 240 may have a shape in
which the top and bottom surfaces thereof have equal widths.
Meanwhile, both of the top and bottom surfaces of the surface
treatment layer 240 may have widths narrower than that of the
bottom surface of the circuit pattern 230.
Accordingly, differently from that of the first embodiment, the
surface treatment layer 240 according to the second embodiment has
an cave structure of protruding outward from only the upper lateral
side of the circuit pattern 230.
As described above, according to the disclosure, the surface
treatment layer 240 including Au is formed utilizing the plating
seed layer 220 used when the circuit pattern 230 is formed, so that
the nickel (Ni) surface treatment layer serving as the seed layer
for the gold (Au) surface treatment layer may be omitted.
In addition, as described above, according to the disclosure, the
conventional nickel (Ni) surface treatment layer is omitted, and
the surface treatment layer 140 including gold (Au) is formed
directly on the circuit pattern 130, thereby increasing the
electrical conductivity, and reducing the electrical resistance.
Accordingly, the RF characteristic may be improved.
In addition, as described above, according to the disclosure, the
surface treatment layer 240 formed on the circuit pattern 230 has
an eave structure of protruding outward from the upper right
lateral side of the circuit pattern 230, so that the mounting area
of the components mounted on the circuit pattern 230 may be
increased. Accordingly, the reliability of a customer may be
improved.
Hereinafter, a method of fabricating the printed circuit board
shown in FIG. 12 will be described with reference to FIGS. 13 to
15.
FIGS. 13 to 15 are sectional views showing the method of
fabricating the printed circuit board shown in FIG. 12 in process
sequence.
First, referring to FIG. 13, after preparing the insulating layer
210, the plating seed layer 220 is formed on the prepared
insulating layer 210.
The plating seed layer 220 may be formed by performing electroless
plating with respect to the insulating layer 110 using metal
including Cu.
The insulating layer 210 may include a thermosetting or
thermoplastic polymeric substrate, a ceramic substrate, an
organic-inorganic composite substrate, or a glass fiber impregnated
substrate. If the insulating layer 210 includes the polymeric
resin, the insulating layer 210 may include epoxy insulating resin,
or may include polyimide based resin.
Next, the circuit pattern 230 is formed by performing
electroplating with respect to the plating seed layer 220 serving
as a seed layer using a conductive material, preferably, the alloy
including Cu.
Thereafter, a mask 225 is formed on the plating seed layer 220.
In this case, preferably, the mask 225 may include a dry film
having strong heat resistance and an easy removable property.
The mask 225 includes an opening B to expose the top surface of the
circuit pattern 230.
The width of the opening B of the mask 225 is narrower than that of
the top surface of the circuit pattern 230.
Accordingly, at least a portion of the top surface of the circuit
pattern 230 is covered by the mask 225. Preferably, the central
area and the left area of the top surface of the circuit pattern
230 are exposed to the outside by the opening B of the mask 225,
and the right edge area of the top surface of the circuit pattern
230 is covered by the mask 225.
Next, referring to FIG. 14, the surface treatment layer 240 is
formed on the circuit pattern 230 by employing the plating seed
layer 220 and the circuit pattern 230 as a seed layer.
In this case, the surface treatment layer 240 has a width equal to
that of the opening B of the mask 225.
The surface treatment layer 240 may be formed of metal including
only Au or the alloy including Au.
When the surface treatment layer 240 is formed of the alloy
including Au, the surface treatment layer 240 may be formed of the
Au alloy including Co. In this case, the surface treatment layer
240 is formed through electroless plating.
Preferably, the surface treatment layer 240 is formed by performing
the electroplating with respect to the plating seed layer 220 which
is the same as the plating seed layer used when the circuit pattern
230 is formed. In other words, the surface treatment layer 240 is
formed through the electroplating as the plating seed layer 220 is
connected with the circuit pattern 230 so that a short occurs
between the plating seed layer 220 and the circuit pattern 230.
The surface treatment layer 240 is formed on the circuit pattern
230 so that the bottom surface of the surface treatment layer 240
directly makes contact with the top surface of the circuit pattern
230.
In this case, the surface treatment layer 240, which exists before
the plating seed layer 220 is removed, includes top and bottom
surfaces having a width narrower than that of the top surface of
the circuit pattern 230.
Accordingly, the top surface of the circuit pattern 230 includes a
portion, which makes contact with the surface treatment layer 240,
and a portion which does not make contact with the surface
treatment layer 240.
Thereafter, referring to FIG. 15, the mask 225 is removed from the
plating seed layer 220.
Then, a process of removing a portion of the plating seed layer
220, which is formed on the insulating layer 210 and has no circuit
pattern 230, is performed.
In other words, after the mask 225 has been removed, the process of
removing the portion of the plating seed layer 220, which is formed
on the insulating layer 210 and has no circuit pattern 230, is
performed. In this case, when the process of removing the portion
of the plating seed layer 220, which is formed on the insulating
layer 210 and has no circuit pattern 230, is performed, a portion
of the plating seed layer 120 which is formed under the circuit
pattern 130 is not removed due to the circuit pattern 130, but only
the portion of the plating seed layer 220 having no circuit pattern
130 is selectively removed.
In this case, a right edge area of the top surface of the circuit
pattern 230 has no surface treatment layer 240. Accordingly, when
the process of removing the plating seed layer 220 is performed,
the right edge area of the top surface of the circuit pattern 230,
which are not covered by the surface treatment layer 240, are also
removed.
In this case, only the upper portion of the circuit pattern 230,
which is not covered by the surface treatment layer 240, is
removed.
Accordingly, the upper right portion of the circuit pattern 230,
which is not covered by the surface treatment layer 240, has a
lateral side with a predetermined curvature differently from that
of the lower portion of the circuit pattern 230.
Accordingly, the bottom surface of the surface treatment layer 240
has a width wider than that of the top surface of the circuit
pattern 230.
The bottom surface of the surface treatment layer 240 includes a
first bottom surface, which directly makes contact with the top
surface of the circuit pattern 230, and a second bottom surface
which does not make contact with the top surface of the circuit
pattern 230 due to the process of removing the plating seed layer
220.
In this case, the first bottom surfaces of the surface treatment
layer 240 may include the central area and a left area of the
bottom surface of the surface treatment layer 240, and the second
bottom surface of the surface treatment layer 240 may include the
right area of the surface treatment layer 240.
Meanwhile, the top and bottom surfaces of the surface treatment
layer 240 may have widths narrower than that of the bottom surface
of the circuit pattern 230.
In addition, the upper right lateral side of the circuit pattern
230 is formed with a predetermined curvature lengthwise.
Accordingly, as shown in FIG. 12, the surface treatment layer 240
has an eave structure of protruding outward from the upper right
lateral side of the circuit pattern 230.
As described above, according to the disclosure, the surface
treatment layer 240 including Au is formed using the plating seed
layer 220 used when the circuit pattern 230 is formed, so that the
nickel (Ni) surface treatment layer serving as the seed layer for
the gold (Au) surface treatment layer may be omitted.
In addition, as described above, according to the disclosure, the
conventional nickel (Ni) surface treatment layer is omitted, and
the surface treatment layer 140 including gold (Au) is formed
directly on the circuit pattern 130, thereby increasing the
electrical conductivity, and reducing the electrical resistance.
Accordingly, the RF characteristic may be improved.
In addition, as described above, according to the disclosure, the
surface treatment layer 240 formed on the circuit pattern 230 has
an eave structure of protruding outward from the upper lateral side
of the circuit pattern 230, so that the mounting area of the
components mounted on the circuit pattern may be increased.
Accordingly, the reliability of a customer may be improved.
FIG. 16 is a sectional view showing the structure of a printed
circuit board according to the third embodiment of the
disclosure.
Referring to FIG. 16, a printed circuit board 300 includes an
insulating layer 310, a plating seed layer 320, a circuit pattern
330, and a surface treatment layer 340.
In this case, since the insulating layer 310 and the plating seed
layer 320 are the same as those of the first embodiment and the
second embodiment, the details thereof will be omitted.
In addition, the circuit pattern 230 according to the second
embodiment includes an upper right lateral side having a
predetermined curvature.
However, the circuit pattern 330 according to the third embodiment
of the disclosure has an upper left lateral side having a
predetermined curvature, and a right lateral side is formed to be
substantially perpendicular to the bottom surface.
FIG. 17 is a sectional view showing a printed circuit board 400
according to a fourth embodiment of the disclosure.
Referring to FIG. 17, the printed circuit board 400 includes an
insulating layer 410, a plating seed layer 420, a circuit pattern
430, a surface treatment layer 440, and a protective layer 450.
In this case, since the insulating layer 410, the plating seed
layer 420, the circuit pattern 430, and the surface treatment layer
440 are the same as those of the printed circuit board according to
the first embodiment of the disclosure shown in FIG. 2, the details
thereof will be omitted.
The printed circuit board 400 according to the fourth embodiment
further includes a protective layer 450 formed on the insulating
layer 410 to cover the surface of the insulating layer 410, the
lateral side of the plating seed layer 420, the lateral side of the
circuit pattern 430, and a portion of the top surface of the
surface treatment layer 440.
The protective layer 450 protrudes from the top surface of the
surface treatment layer 440 by a predetermined height.
The protective layer 450 may include solder resist, protect the
surface of the insulating layer 410, and at least a portion of the
top surface of the surface treatment layer 240 of the circuit
pattern formed on the insulating layer 410.
The protective layer 450 according to the fourth embodiment covers
the exposed entire surface of the insulating layer 410.
FIG. 18 is a sectional view showing a printed circuit board
according to a fifth embodiment.
Referring to FIG. 18, a printed circuit board 500 includes an
insulating layer 510, a plating seed layer 520, a circuit pattern
530, a surface treatment layer 540, and a protective layer 550.
Since the insulating layer 510, the plating seed layer 520, the
circuit pattern 530, and the surface treatment layer 540 are the
same as those of the printed circuit board according to the first
embodiment of the disclosure shown in FIG. 2, the details thereof
will be omitted.
The printed circuit board 500 according to the fifth embodiment
further includes the protective layer 550 formed on the insulating
layer 510 to cover a portion of the surface of the insulating layer
510.
The protective layer 550 is formed on the insulating layer 510 and
spaced apart from the circuit pattern 530 by a predetermined
distance.
The protective layer 550 may include solder resist, protect the
surface of the insulating layer 510, and expose the top surface of
the surface treatment layer 540 of the circuit pattern formed on
the insulating layer 510 and a portion of the surface of the
insulating layer 510.
According to the embodiment of the disclosure, the surface
treatment layer is formed by utilizing a removable film-type
material and a plating seed layer used in the circuit pattern, so
that the electrolytic surface treatment and the electroless surface
treatment may be selectively used without the limitation on the
design.
According to the embodiment of the disclosure, the surface
treatment layer including Au is formed using the plating seed layer
used when the circuit pattern is formed, so that a Ni surface
treatment layer serving as a seed layer for the Au surface
treatment layer according to the related art may be omitted.
Accordingly, the thickness of a product may be reduced, and product
cost may be reduced due to the omission of the Ni surface treatment
layer.
In addition, according to the disclosure, the conventional nickel
(Ni) surface treatment layer is omitted, and the surface treatment
layer 140 including gold (Au) is formed directly on the circuit
pattern 130, thereby increasing the electrical conductivity, and
reducing the electrical resistance. Accordingly, the RF
characteristic may be improved.
Further, according to the embodiment of the disclosure, the surface
treatment layer formed on the circuit pattern has an cave structure
of protruding outward from the upper lateral side of the circuit
pattern, so that the mounting area of the components mounted on the
circuit pattern may be increased. Accordingly, the reliability of a
customer may be improved.
Any reference in this specification to "one embodiment," "an
embodiment," "example embodiment," etc., means that a particular
feature, structure, or characteristic described in connection with
the embodiment is included in at least one embodiment of the
invention. The appearances of such phrases in various places in the
specification are not necessarily all referring to the same
embodiment. Further, when a particular feature, structure, or
characteristic is described in connection with any embodiment, it
is submitted that it is within the purview of one skilled in the
art to effect such feature, structure, or characteristic in
connection with other ones of the embodiments.
Although embodiments have been described with reference to a number
of illustrative embodiments thereof, it should be understood that
numerous other modifications and embodiments can be devised by
those skilled in the art that will fall within the spirit and scope
of the principles of this disclosure. More particularly, various
variations and modifications are possible in the component parts
and/or arrangements of the subject combination arrangement within
the scope of the disclosure, the drawings and the appended claims.
In addition to variations and modifications in the component parts
and/or arrangements, alternative uses will also be apparent to
those skilled in the art.
* * * * *